The subject invention relates to a cantilever push tab for a medical device. More specifically, the cantilever push tab is especially adapted for use with introducer needle assemblies that may be used in conjunction with intravenous catheters, as well as catheter introducers and guidewire introducers.
In order properly to place medical devices such as intravenous (xe2x80x9cIVxe2x80x9d) catheters into a patient, the catheter is typically mounted over an introducer needle having a sharp distal tip. At least the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitates insertion of the catheter into the blood vessel. The distal tip of the needle preferably extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient""s skin.
The catheter and introducer needle assembly is inserted at a shallow angle through the patient""s skin into a blood vessel. In typical assemblies, the clinician confirms that there is flashback of blood in a flashback chamber associated with the needle assembly in order to verify proper placement of the catheter in the blood vessel. The flashback chamber is typically formed as part of the needle hub. Once proper placement of the catheter into the blood vessel is confirmed, the clinician applies pressure to the blood vessel by pressing down on the patient""s skin over the blood vessel distal of the needle and the catheter. This finger pressure occludes or at least minimizes further blood flow through the needle and the catheter. The clinician then withdraws the needle, leaving the catheter in place for use in accordance with standard medical technique.
Clinicians may use various techniques for inserting a catheter into a patient. This variety of techniques also comes into play because there are different types of catheters, such as straight and ported catheters, that may be used. A ported catheter includes a radially extending side port integral with the catheter adapter. See for example the catheter disclosed in U.S. Pat. No. 5,098,405. In a ported catheter, the fluid-handling device normally connected to the catheter is connected to the proximal end of the catheter adapter with the side port providing access to the catheter and thus the patient""s vasculature for intermittent injections of medicaments. Such ported catheters are typically used in Europe. With a ported catheter, the clinician typically grasps the assembly by placing the thumb of one hand on the proximal end of the needle hub and the forefinger or middle finger of that same hand on the side port of the catheter adapter and, where there is a wing, the other finger is placed on the wing. A straight catheter does not include a side port so that the fluid-handling device is connected to the proximal end of the catheter adapter. See for example the catheters disclosed in U.S. Pat. Nos. 4,193,400 and 5,685,855. Such straight catheters are typically used in the United States. With a straight catheter, the clinician typically grasps the assembly by placing the thumb and forefinger or middle finger of one hand on either side of the needle hub. If the middle finger is used, the forefinger of that hand can be used to push against a push tab that may be formed on the top of the catheter adapter to facilitate the advancement of the catheter off of the needle. Alternatively, the other hand can be used to push against the push tab.
Once a clinician learns a particular technique to insert a particular type of catheter into a patient, that clinician will typically continue to use that insertion technique and the catheter associated with that technique, for inserting the catheter into a patient. The technique sensitive nature of catheter insertion procedures is exacerbated by the structural differences between ported catheters and straight catheters. Thus, a clinician trained to insert a ported catheter may have difficulty adjusting to inserting a straight catheter. Similarly, a clinician trained to insert a straight catheter may have difficulty adjusting to inserting a ported catheter.
This requires medical device manufacturers to produce and maintain an adequate supply of both ported and straight catheters in order to meet the needs of clinicians. This is costly and potentially wasteful for the manufacturer.
It is therefore an object of this invention to provide an introducer needle assembly for a medical device, such as an IV catheter, to allow clinicians to use virtually any clinically acceptable technique for inserting the catheter.
It is another object of this invention to provide an introducer needle assembly for a medical device, such as an IV catheter, to allow clinicians to insert a catheter into a patient without regard to whether that clinician has been trained to use ported catheters or straight catheters.
The IV catheter typically used with the introducer needle assembly of this invention is coaxially disposed over the introducer needle with the distal portion of the catheter tightly engaging the outer surface of the introducer needle. This prevents peelback of the catheter and facilitates insertion of the catheter into the patient""s blood vessel. Prior to use, the catheter is located about the introducer needle so that the sharp distal tip of the introducer needle is distal of the distal end of the catheter. The proximal end of the catheter is connected to a catheter adapter.
The introducer needle has a sharp distal tip and a proximal end connected to the distal end of a needle hub. A flashback chamber may be defined in the needle hub. Where such a flashback chamber is used, a vented plug is located in the open proximal end of the flashback chamber to allow air to escape from the flashback chamber when blood enters the flashback chamber from the introducer needle. Alternatively, the introducer needle could define a notch, i.e. an opening in the sidewall of the introducer needle, and an integrated extension tube could extend from the catheter adapter. In this embodiment, flashback of blood can be observed in the catheter and the integrated extension tube as blood flows through the notch into the annular space between the needle and the catheter and into the extension tube once a successful venipuncture has been made.
A needle shield is movably disposed about the introducer needle and located distally of the needle hub. The needle shield is defined by a housing having an internal cavity through which the introducer needle extends. A lock associated with the needle shield prevents unwanted distal movement of the introducer needle once the introducer needle has been proximally withdrawn into the needle shield. Also associated with the needle shield is a means for preventing unwanted proximal movement of the introducer needle once the sharp distal tip of the introducer needle has been proximally withdrawn into the needle shield.
A cantilever push tab is associated with the needle shield and extends distally from the distal end of the needle shield. As its name implies, the cantilever push tab includes a cantilever portion that extends distally from the needle shield, preferably from an exterior surface of the needle shield, and an upstanding tab portion adjacent to the distal end of the cantilever portion. This configuration causes the upstanding tab to extend over the proximal portion of the catheter adapter and allows a clinician to insert a catheter into a patient using virtually any clinically acceptable technique. For example, the clinician can use a single-handed technique that is typically used for inserting a ported catheter. In addition, a clinician can initially disregard the cantilever push tab and insert a catheter using a single-handed technique typically used for inserting a straight catheter and use the cantilever push tab to advance the catheter off of the introducer needle. Alternatively, a clinician can use a two-handed technique and push against the cantilever push tab with her other hand to insert the catheter into a patient. As can be seen from the foregoing discussion, the cantilever push tab provides maximum flexibility and allows a clinician to insert a catheter used in conjunction with an introducer needle assembly of this invention with virtually any clinically acceptable technique.